Chapter 5

# Chapter 5 - Chapter 5 Newtonian Mechanics Ch 5 Force and...

This preview shows pages 1–10. Sign up to view the full content.

Chapter 5 Newtonian Mechanics

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Ch 5 Force and Motion Summery of Motion Force Newton’s 1 st Law Reference Frames Newton’s 2 nd Law Mass Free Body Diagram
What did we learn so far? How do objects move? Position, velocity and acceleration as a function of time. Example : 1D-motion with a constant acceleration. 3-d motion with constant acceleration r r ( t ), r υ ( t ), r a ( t ) x ( t ) = x 0 + 0 t + 1 2 at 2 ( t ) = 0 + at a = costant

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Why do objects move? Historical prospective: Aristotle: The natural state of an object is to be at rest. For an object to move with a constant velocity a force needs to be applied. Galileo Galilei: He recognizes that if a moving object is not disturbed by external forces it will keep moving at a constant rate. Frictionless surface r υ = constant
Newton’s First Law Formulation: If no force acts on a body, the body’s velocity cannot change. If no force acts on an object it remains at rest or it continues its linear uniform motion. Example:

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
A few pointers A linear and uniform motion is as “natural” for a body as for it to be at rest. The presence of an acting force is not a reason by itself for an object to be moving. If a body is not moving uniformly, there is a force acting on it! If a body is moving on a curved trajectory there is definitely a force acting on it. a 0
Force The force is a vector : Magnitude Direction Application point The force has 3 components: Unit: N (Newton) 1N is the force that results in acceleration of 1 m/s 2 when applied to a standard body with mass 1 kg . r F = F x ) i + F y ) j + F z ) k F x F y F z r F x y z r F

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Net Force: Forces add and subtract as vectors . The sum of all forces acting on a single body is called net force (resulting force). Principle of superposition : The effect of all forces acting on a single, point mass is equivalent to the effect of a single force (the net force) acting on this body. r F net r F 1 r F 2 r F net r F net = r F 1 + r F 2 + r F 3 + ...
Newton’s First Law : an object will stay at rest , or maintain its motion at a constant velocity and in a straight line as long as no force is exerted on the object , or all forces cancel each other (F net =0) Says who? An observer at rest, or moving at a constant speed. G

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

## This note was uploaded on 03/12/2010 for the course PHY 2049 taught by Professor Any during the Spring '08 term at University of Florida.

### Page1 / 36

Chapter 5 - Chapter 5 Newtonian Mechanics Ch 5 Force and...

This preview shows document pages 1 - 10. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online